Exploring the 90% Effective Ventilation Pressure (EP90) for Esophageal Insufflation Avoidance During Anesthesia Induction: The aim is to determine the optimal ventilation pressure for esophageal insufflation avoidance during anesthesia induction and to explore its guiding significance for anesthesia management. The goal is to provide a more precise and personalized ventilation pressure setting standard for clinical anesthesia, thereby enhancing the safety of the anesthesia induction phase.
Age: 18-65 years, regardless of gender;
ASA classification: I-III;
Scheduled for elective general anesthesia surgery;
BMI: 18.0-28.0 kg/m²;
Pregnant or breastfeeding women;
History of upper gastrointestinal diseases such as gastroesophageal reflux disease, peptic ulcers, or hiatal hernia;
Recent (within 2 weeks) respiratory infections, chronic cough, similar symptoms, and other known or predictable respiratory system diseases;
Need for emergency surgery or airway obstruction after anesthesia induction requiring urgent intubation;
Sequential
Ultrasonic and inflation determination
Other interventionBefore induction, during ventilation, and after intubation, the anesthesiologist used a 7-14 MHz linear array probe for transverse (supraclavicular) positioning to monitor the left paratracheal esophageal region in real time. The main criterion for assessment was the absence of esophageal gas during ventilation, which was considered a positive response. If gas was detected entering the esophagus on ultrasound, it was recorded as a negative response. Additionally, the anesthesiologist performed a preoperative ultrasound examination of the gastric antrum to record baseline gastric antrum parameters. After successful tracheal intubation, a follow-up ultrasound of the gastric antrum was conducted to obtain postoperative gastric antrum parameters.
EP90
The 90% effective ventilation pressure (EP90) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 90% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
EP95
The 95% effective ventilation pressure (EP95) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 95% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
EP98
The 98% effective ventilation pressure(EP98) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 98% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
Ventilation-related respiratory parameters
pulse oxygen saturation (SpO₂) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Ventilation-related respiratory parameters
end-tidal carbon dioxide (EtCO₂) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
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